As it has been said a picture is worth a thousand words and so it is with graphics too. 
A well constructed graph can summarize information collected from tens to hundreds or even thousands of data points. But not every graph has the same power to convey complex information clearly. [Read more…] about Member Training: An Introduction into the Grammar of Graphics
OptinMon 10 - 14 Steps
Member Training: Writing Study Design and Statistical Analysis Plans
One component often overlooked in the ‘Define & Design’ phase of a study, is writing the analysis plan. The statistical analysis plan integrates a lot of information about the study including the research question, study design, variables and data used, and the type of statistical analysis that will be conducted.
[Read more…] about Member Training: Writing Study Design and Statistical Analysis Plans
Why Statistics Terminology is Especially Confusing
The field of statistics has a terminology problem.
It affects students’ ability to learn statistics. It affects researchers’ ability to communicate with statisticians; with collaborators in different fields; and of course, with the general public.
It’s easy to think the real issue is that statistical concepts are difficult. That is true. It’s not the whole truth, though. [Read more…] about Why Statistics Terminology is Especially Confusing
Four Weeds of Data Analysis That are Easy to Get Lost In
Every time you analyze data, you start with a research question and end with communicating an answer. But in between those start and end points are twelve other steps. I call this the Data Analysis Pathway. It’s a framework I put together years ago, inspired by a client who kept getting stuck in Weed #1. But I’ve honed it over the years of assisting thousands of researchers with their analysis.
[Read more…] about Four Weeds of Data Analysis That are Easy to Get Lost In
The Difference Between Model Assumptions, Inference Assumptions, and Data Issues
Have you ever compared the list of model assumptions for linear regression across two sources? Whether they’re textbooks, lecture notes, or web pages, chances are the assumptions don’t quite line up.
Why? Sometimes the authors use different terminology. So it just looks different.
And sometimes they’re including not only model assumptions, but inference assumptions and data issues. All are important, but understanding the role of each can help you understand what applies in your situation.
[Read more…] about The Difference Between Model Assumptions, Inference Assumptions, and Data Issues
Chi-Square Test of Independence Rule of Thumb: n > 5
Ever hear this rule of thumb: “The Chi-Square test is invalid if we have fewer than 5 observations in a cell”.
I frequently hear this mis-understood and incorrect “rule.”
We all want rules of thumb even though we know they can be wrong, misleading, or misinterpreted.
Rules of Thumb are like Urban Myths or like a bad game of ‘Telephone’. The actual message gets totally distorted over time.
[Read more…] about Chi-Square Test of Independence Rule of Thumb: n > 5